Fixes Issue #29 Failures in test_make_test_datasets.py

This addresses issue #29 (Failure in test_make_test_datasets.py) by addressing one issue with a list comprehension in exclude_tip (it referenced a tree tip instead of the tips name) in make_test_datasets.py, and by allowing equivalent trees (e.g. three taxon trees with sister nodes printed in swapped order) to pass the test code in test_make_test_datasets.py.

Finally, superfluous print statements in make_test_datasets.py were set to print if verbose only, and the default verbose value was set to False by default for functions where stdout is useful only for debugging.